पिछली (अज्ञात) तिथि का SQL मान

आप चाहते हैं lag() :

select 
    articleid, 
    amount,
    date,
    lag(date) over(partition by articleid order by date) prevdate,
    lag(amount) over(partition by articleid order by date) prevamount
from table1
order by articleid, date desc